Classe:
[code=vbnet]Public Class discriminant
    'door Wim Mariën
    'http://www.gdx.be/

    Private dblA, dblB, dblC As Double
    Private dblD As Double
    Private dblX, dblY As Double

    Public WriteOnly Property A() As Double
        Set(ByVal value As Double)
            dblA = value
        End Set
    End Property

    Public WriteOnly Property B() As Double
        Set(ByVal value As Double)
            dblB = value
        End Set
    End Property

    Public WriteOnly Property C() As Double
        Set(ByVal value As Double)
            dblC = value
        End Set
    End Property

    Public ReadOnly Property D() As Double
        Get
            Return dblD
        End Get
    End Property

    Public ReadOnly Property X1() As Double
        Get
            Return dblX
        End Get
    End Property

    Public ReadOnly Property X2() As Double
        Get
            Return dblY
        End Get
    End Property

    Public Sub bereken()
        dblD = dblB ^ 2 - (4 * dblA * dblC)
        If (dblD > 0) Then
            dblX = (-dblB - Math.Sqrt(dblD)) / (2 * dblA)
            dblY = (-dblB + Math.Sqrt(dblD)) / (2 * dblA)
        ElseIf dblD = 0 Then
            dblX = (-dblB) / (2 * dblA)
            dblY = dblX
        Else
            dblX = CDbl(False)
            dblY = CDbl(False)
        End If

    End Sub
End Class